Safety push buttons of this type are described, for example, in U.S. Pat. Nos. 3,484,023 and 3,848,778 in the name of Philip Meshberg. These safety actuators include a push button having a jet orifice and fitted over the rod of a valve mounted in the opening to the container. They also include a sleeve having means for permanently fixing the actuator to the container. When in an "active" orientation, the push button is axially slidable inside the sleeve to open the valve and thus cause liquid contained inside the container to be expelled. The push button is also rotatable from said active orientation to an "inactive" orientation in which it is prevented from moving axially, thereby preventing the valve from being released.
These actuators, and other similar actuators, suffer from various drawbacks: Before use the push button must be rotated relative to the sleeve, but since the sleeve is not locked and may rotate with the actuator, the user needs to use both hands to be sure of unlocking the actuator. This is not desirable for self-defense aerosols that project tear-gas or the like. In case of need the aerosol must be instantly available, and it is highly advantageous for it to be useable singlehanded. The way in which the sleeve is fixed to the can as described in the above-mentioned U.S. patents is not suitable for preventing rotation. Furthermore, a different size of push button must be designed for each size of can.
Preferred embodiments of the present invention avoid the above drawbacks.